Retinoic acid modulates stem cell factor secretion by human neuroblastoma cell lines

The hemopoietin stem cell factor (SCF) and its receptor c-kit are expressed in some tumoral cells, including neuroblastoma (NB) cells. We have investi gated the effect of retinoic acid (RA) one of the most active differentiati ng agents on human NE cells, on the SCF production by human neuroblastoma c ell lines. SCF concentration was determined by immunoenzymatic assay in the supernatants of seven neuroblastoma cell lines. All cell lines except one showed detectable amounts of SCF in the supernatant in basal culture condit ions A progressive increase pattern of the SCF concentration over time, was common to all SCF secreting cell lines, both unstimulated and RA-stimulate d. Moreover, after 48 and 72 hours-exposure to RA, SCF concentrations were higher than in the untreated controls (p<0.01). Membrane SCF mRNA isoform w as also detected by reverse-transcription polymerase chain reaction. These effects demonstrated that RA, besides inducing neuronal differentiation enh anced SCF production in neuroblastoma cell lines.